LiCl Photodissociation on Graphene: A Photochemical Approach to Lithium Intercalation

Abstract

The interest in the research of the structural and electronic properties between graphene and lithium has bloomed since it has been proven that the use of graphene as an anode material in lithium-ion batteries ameliorates their performance and stability. Here, we investigate an alternative route to intercalate lithium underneath epitaxially grown graphene on iridium by means of photon irradiation. We grow thin films of LiCl on top of graphene on Ir(111) and irradiate the system with soft X-ray photons, which leads to a cascade of physicochemical reactions. Upon LiCl photodissociation, we find fast chlorine desorption and a complex sequence of lithium intercalation processes. First, it intercalates, forming a disordered structure between graphene and iridium. On increasing the irradiation time, an ordered Li(1 × 1) surface structure forms, which evolves upon extensive photon irradiation. For sufficiently long exposure times, lithium diffusion within the metal substrate is observed. Thermal annealing allows for efficient lithium desorption and full recovery of the pristine G/Ir(111) system. We follow in detail the photochemical processes using a multitechnique approach, which allows us to correlate the structural, chemical, and electronic properties for every step of the intercalation process of lithium underneath graphene.

Loofah Sponge-Derived Hygroscopic Photothermal Absorber for All-Weather Atmospheric Water Harvesting

“…Also, this further proved that LiCl was still stable in LBC. As shown in Figure S18, the Li 1s X-ray photoelectron spectroscopy (XPS) spectrum of BC/CNT and loofah show peaks at 55.3 and 55.6 eV, which correspond to LiCl . No collapse or destruction was observed in the holes of the loofah fiber, and LiCl still evenly covered the section.…”

“…As shown in Figure S18, the Li 1s X-ray photoelectron spectroscopy (XPS) spectrum of BC/ CNT and loofah show peaks at 55.3 and 55.6 eV, which correspond to LiCl. 57 No collapse or destruction was observed in the holes of the loofah fiber, and LiCl still evenly covered the section. Similarly, continuous photothermal conversion did not destroy the structure of BC/CNT film, which remained flat.…”

Electronic Interactions and Stability Issues at the Copper-Graphene Interface in Air and in Alkaline Solution Under Electrochemical Control

“…The issue of electronic decoupling at the graphene-Cu interface was mainly investigated in the literature on polycrystalline Cu supports in the context of intercalation of oxygen-containing species (e.g., oxygen, water vapor) from ambient air. Studies performed with x-ray photoelectron spectroscopy (XPS) and Raman spectroscopy showed that electronic decoupling of graphene from the substrate accompanies the intercalation of such species and the formation of an oxide layer on the Cu surface [24][25]. Interestingly, annealing such samples in vacuum reverses the electronic decoupling as the oxide is reduced [24].…”